The carbohydrate chains of thyroxine binding globulin have been shown to interact with protein residues and influence its properties. Various fluorescent parameters were used to evaluate the properties of the glycoprotein during enzymatic hydrolysis by neuraminidase and a mixture of glycosidases which remove 86% of the carbohydrates. The behavior of the membrane of coated vesicles (CVs) was compared with and without its coat by the fluorescent properties of pyrene and cis- and trans parinaric acid. The results indicate that coating the membrane (with clathrin) reduced its fluidity. A conformational change has been observed in clathrin between pH 7 and 6 which appears to initiate its polymerization.